1. Field of the Invention
The present invention relates generally to the measurement of the depth of a quantity of liquid in a tank, container or the like, and, more particularly, to an improved liquid depth measurement device having a water level indicator and a fluid sampling device.
2. Description of the Prior Art
There are many instances in which it is desirable or essential to be able to measure the depth of a fluid in large under ground and above ground storage tanks, container, or the like to determine the volume of the fluid contained therein. Large underground or above-ground bulk storage tanks are typically situated at gasoline service stations, convenience stores, factories, office buildings, truck stops, etc. In addition, the same requirements apply to numerous smaller tanks and containers. Dipsticks are commonly used primarily as back up to automated leak detection and inventory control systems that are mandatory for the large bulk storage tanks or as the primary method for the measurement of smaller tanks and containers.
The most frequently used device for this purpose is the common wooden dip stick which is inserted into the tank, container or the like until its lower end strikes the bottom after which the gauge is raised up and the fluid depth is determined by noting the upper extent of the wetted portion on the pole (wet line). A typical dipstick has lines of demarcation marked off along its length so that the liquid depth can be determined after the dipstick is withdrawn from the tank so that the location of the wet line can be seen.
Wooden gauge dipsticks suffer from many deficiencies that make them less than satisfactory for accuracy, durability or dependability. They do not meet current stringent requirements for accountability for tank leakage and product inventory control. For example, scales are neither precise nor protected and thus are subject to wear and tear with repeated use. The unprotected blunt end of the wood sticks damages the bottom of the tanks through pinning action and cause eventual erosion of the tank bottoms. Wood sticks are subject to splintering, breakage and warping requiring frequent replacement. The reliance on the wet line as the indicator of product level is inaccurate and at best is an approximate reading. The wet line is the result of residual fluid deposited on the scale at the time of stick submersion and withdrawal from the tank and is subject to rapid evaporation. The scales are difficult to read in wet weather conditions and night tank readings. These conditions require the need for multiple readings and are time consuming. Wood sticks when inserted in tanks rapidly are subject to splashing that may result in inaccurate measurements.